Dental implants are biocompatible functional devices that are placed into bones for substituting an extracted tooth or providing support to fixed or mobile prostheses. The goal of implant design is to provide sufficient initial stability and accomplish osteointegration as early as possible after implantation. Implants are kept load-free for 3 to 6 months following primary surgery. During this period, new regular bone that will stand against the occlusive loads is formed around the implant (osteointegration); so the implant becomes stable enough to resist functional forces created during mastication. Following this stage, prosthetic restoration is done onto the implant to obtain a functional implant.
Magnitude of mechanical stress on alveolar bone depends on the diameter and length of the implant; proper placement of implants with respect to the direction of the forces applied; the number of implants and distribution of the forces. Increasing length of the implant increases its load-bearing surface. Increased length is also crucial for primary stability. Implant should resist shearing and torque forces when abutment is mounted. Increased length also reduces the stress applied on the neck of the implant. Implant body design, screw geometry and surface characteristics are continuously being improved to strengthen the implant-tissue interface, and to attain ideal load transfer; eventually to increase the success and survival of the implant.
High number of anatomic spaces and important nerves in the oral region limits the length of the implants to be used and mandates a detailed examination. If occlusive forces are increased, larger and longer implants should be used. However, confined width and length of the bone restricts the use of implants with appropriate length and width. This negatively affects the long-term success of the implant.